T-square.



J. A. MOFFATTl T-SQUARE, I APPLICATION FILED MAR. 20, I915.

Patented Aug. 10, 1915.

UNITED ii -iii. ZTES EATENT @FFEQE.

JQHN A. IVIQFFATT, OF SUTTQN, NORTH DAKOTA.

T-SQUAPIE.

Application filed March :20, 1915.

To all whom it may 0' Be it known that Jens A. hilOFFATT, a citizen of the United States, residing at Sutton, in the county of Griggs and State of North Dakota, have invented certain new and useful Improvements in T-Squares, of which the following is a specification.

My invention relates to improvements in rule-blades provided with a scale or scales.

An important object of the invention is to provide means for securing a scale-blade to a rule-blade without impairing the use of either blade, with the scale or scales of the scale-blade adjacent the longitudinal edge or edges of the rule-blade, covered for protection from ink or the like and readily visible for convenient use.

A further object of the invention is to provide means of the above mentioned character, which are light, simple in construction, inexpensive to manufacture, and convenient in use.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same, Figure l is a side elevation of apparatus embodying my invention, Fig. 2 is a similar view of ti c scaleblade removed, Fig. 3 is a transverse sectional view taken on line 33 of Fig. 1, Fig. 4 is a similar view taken on line M of Fig. 1, and, Fig. 5 is a similar view taken on line of Fig. 2.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment. of my invention. the numeral 43 designates a T-square as a whole, embodying a head 7. to which is rigidly secured a ruleblade, designated as a whole by the numeral 5'5. This rule-blade is rigidly secured to the head 7 at a right anghi thereto. as is customary. \Vbile l have shown this rule blade as embodied in a T-sipiarmit is to be understood that the invention is in no sense rostricti'd to such :1 construction, as it may be practised with some degree ol sui-vi-ss by dispensing with the head T. The blade H is provided at its free end with a suspension opening 8', as shown.

The rulc-blade H roni irisos a llat blade or strip 5 preferably formed ol wood. to the longitudinal edges of which are secured guide strips 10, preferably having a tongue Specification of Letters Patent.

Patented Aug. 10, 1915.

Serial No. 15,720.

and groove connection therewith, as shown at 11, and cemented or otherwise attached thereto. These guide strips are substan tially thicker than the blade 9, and extend for a substantial distance beyond one side of the blade, as shown. The guide strips 10 are provided upon their inner sides and contiguous with the side of the blade 9, with undercut longitudinal grooves 12, preferably V-shaped in cross section, and decreasing in width outwardly. It is to be understood that the exact shape of the grooves 12 13 considered immaterial. 'The guide strips 10 are formed of a light transmitting material, and may be transparent or translucent, such material being preferably celluloid, artificial amber, real amber, or the like.

The numeral 13 designates a scale-blade as a whole, preferably formed of wood. This scale-blade is preferably of the shape in cross section, as shown, with a longitudinal recess 14 upon its inner or lower side. The scale-blade 13 has its longitudinal edges 15 beveled or tapered, as shown, to snugly fit within the under cut grooves 12 of the guide strips 10. This scale-blade is provided upon the beveled or tapered edges 15 thereof, with scales 10, preferably having different graduations. In order that the scale-blade 13 may be conveniently longitudinally adjusted upon the rule-blade 8 or removed there from when desired, it is provided at a point preferably cquidistantly spaced from the ends thereof, with finger openings 17, separated by a transverse. strip 18, integral with the scale-blade, as shown.

In the use of the T-square, it is apglied to the drawing board in the usual manner, and the sca.lcblade 13 may be conveniently longitudinally adjusted upon the rule-blade, and when desired removed therefrom, whereby another scale-blade having dili'ercnt scales upon its longitudinal edges, may be arranged upon and secured to the ruleblade.

lt is to be understood that the form of my invention herewith shown and described. is to be taken as a preferred example of the same, and that various changes in thcshapc, size. and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim 1. The combination with a rule-blade pro vided at one longitudinal edge with a light transmitting guide-strip provided upon its inner side with an under cut groove, of a scale-blade adapted to be mounted upon the rule-blade and having one longitudinal edge thereof adapted for insertion within the under cut groove of the guide strip, and means to hold the scale blade in position against the guide strip substantially as described.

2. The combination with a rule-blade having light transmitting uide strips secured to its opposite longitudmal edges and provided upon their inner sides with under cut grooves, of a scale-blade provided upon its opposite edges with scales and adapted to be arranged upon the rule-blade with its longitudinal edges and scales arranged beneath the top wallsof the grooves.

3. A rule-blade provided upon its opposite longitudinal edges with light transmitsubstantially V-shaped in cross section, of

a scale-blade longitudinally adjustably mounted upon the rule-blade and having longitudinal beveled scale carrying edges adapted to fit within said grooves.

In testimony whereof I affix my signature in presence of two witnesses.

' JOHN A. MOFFATT.

Witnesses:

H.'B. HANSON, P. J DAVIDSON. 

